The Simplex Gas Engine. 701 •was the cause of failure.* In the Simplex engine a constant •srrower of sparks takes place in the chamber x, the current passing through the insulator u and back by v. In the figure the cylinder is being charged from s, through Q, but when the slide moves to the right, R connects w with x, and ignition occurs •with certainty. (See App. /,/. 773, and App. IV., p. 963.) We may now describe the SIMPLEX ENGINE (Systeme Delamare- Deboutteville et Malandin), Figs. 683 to 688, as a type of a •well-designed gas engine. A is the cylinder, supported on the •bed plate H, and surrounded by a water jacket B, which also protects the slide casing and exhaust outlet; N is the mixing •chamber, and c the piston or plunger. D is the connecting rod, E the crank, F the balance weights, R the crank shaft, and G G the 'fly wheels, having a pulley p attached for driving purposes. Pipe j :is always open to air, and the gaspipe K admits gas when cock L is opened. But such gas is only allowed to enter the cylinder .at proper times, viz., when the charging valve M is opened by projection h on the slide spindle g. As the cycle occupies two revolutions, the shaft Q (which moves the slide d backward and forward through the disc crank/) makes two rotations to one on the main shaft, and the wheels at R and s together have a velocity Tatio of 2:1. The charging and ignition having been described *the governing and exhaust arrangements remain. Taking the former, shewn in Figs. 687 and 688, the method adopted, as in -other gas engines, is to cut out one or more chargings when the •engine speed increases. Upon the spindle h is a small tapered 6 rocker '/, &&& when this is allowed to catch the stem k of the •charging valve the latter is opened The governor is a pendulum n /, whose lower end is lifted to the right by the rocker /, and, being allowed to return freely, its time of fall is invariable. Noting that the rocker/ is constantly depressed, as in Fig. 688, •by a spring, suppose engine speed to be normal, and / to be •moved to the right, lifting the pendulum. Returning, the pen- dulum bears slightly upon the rocker, catch m lifts/ to the hori- zontal, and the valve is opened. But if the slide travel too quickly, m misses/when returning, and the result is a 'misfire,' * M. Deboutteville. iodines to the former, Prof. Wm. Robinson to the latter (muse.